Telephone system



Dec. '10, 1940. w. SAVILLE ET AL' TELEPHONE SYSTEM Filed Nov. 22, 1937 4 Sheets-Sheet l 4 1D o v 2 3 ID r J R O waww m E MW cw M H INVENTORS WILL/E .SAV/LLE 157w uugu WILLIAMS ATTY.

1940 w. sAvlLLE. ET AL ,224,701

TELEPHONE SYSTEM Filed Nov; 22, 1937 4 Sheets-Sheet 2 "To JUNCTION INVENTORS WILL/E SAV/LLE Dec. 10, 1940. w sAVlLLE ETAL 2,224,701

TELEPHONE SYSTEM Filed Nov. 22, 1937 4 Sheets-Sheet 5 FROM SELECTOR MULUDLE INVENTORS WILL/E SAV/LLE jig/N HUGH WILLIAMS. A51)? Dec. 10, 1940.

Filed Nov. 22, 1937 4 Sheets-Sheet 4 TO ,JUNCTION U M 63 :1? g k; i 1 k2 E INVENTORS WILLIE SAV/LLE ATT.

Patented Dec. 10, 1940 UNITED STATES PATENT OFFICE TELEPHONE SYSTEM Application November 22, 1937, Serial No. 175,822 In Great Britain December 7, 1936 9 Claims.

The present invention relates to improvements in telephone or like impulse sending systems and is more particularly concerned with impulse repeating devices of the type adapted to receive trains of impulses on a storage device and to retransmit them in corrected form to succeeding switches, in some cases after a delay which varies in accordance with the nature of the switching operations to be performed preparatory to their 9 despatch. The invention moreover relates to impulse regenerators of the type in which the registering and transmitting members follow one another conveniently along a circular path. The object of the invention is to provide a means whereby the scope of applicatlon'of impulse regenerators of this type may be widened and whereby the efiiciency of arrangements embodying it may be increased.

According to one feature of the invention in an impulse regenerator of the type wherein a stepping member is moved by incoming impulses away from a co-operating member which moves towards the first member to transmit correspondor ing regenerated impulses, if the first member is moved a predetermined number of steps away from the second member contact springs are operated to produce suitable circuit changes.

According to another feature of the invention in an impulse regenerator of the type wherein a stepping member is moved by incoming impulses from a co-operating member which moves towards the first member to transmit correspond-, ing regenerated impulses, if the first member is advanced so far ahead of the second member that it cannot satisfactorily operate in response to a further train of impulses contact springs are operated to prevent any further operation of the first member.

A further feature of the invention is that in an impulse regenerator of the type wherein a stepping member is moved by incoming impulses in a circular path away from a co-operating member which moves towards the first member to transmit corresponding regenerated impulses, if 5 the first member is advanced a complete revolution so as to encounter the second member contact springs are operated and the second memher is released.

The invention will be better understood from the following description of two methods of carrying it into efiect reference being had'to the accompanying drawings comprising Figs. 1-4. These should be arranged side by side in pairs r to form circuit diagrams of impulse repeaters embodying the invention.

In each case it is assumed that use is made, of a regenerator of the type disclosed in J. W. McClew and C. R. Woodlands application No.

79,830, filed May 19 36, and that the repeater is connected up to an outgoing junction which is terminated at the distant end in a finder switch. Retransmission of stored pulses is delayed until a signal is received from the distant exchange to indicate that the finder has found the calling junction on substantially the lines disclosed in Figs. 4 and 5 of our application No. 109,072 filed November 4, 1936. It will be appreciated that if there is sufficient delay in the finding operation the regenerator may become full to capacity and y be unable to accept further trains of pulses representing digits dialled.

In the circuit shown in Figs. 1 and 2 the invention has been appliedin such a manner that if the regenerator becomes full to capacity the succeeding apparatus taken into use is released. the regenerator is restored to normal and busy tone is returned to the calling path while in the circuit of Figs. 3 and 4 the invention has been applied in such a manner that if necessary a second regenerator is connected up in series, thereby doubling the available storage capacity.

The circuit diagrams as shown are arranged so that on reply of the called party the transmission bridge is removed and the speaking leads are connected straight through to the outgoing junction extending to the distant exchange apparatus. By removal of the dotted connections and the insertion of others which will be described subsequently, the transmission bridge may be retained throughout the connection and, on reply of the called party a reversal is repeated to the calling side of the circuit for supervisory or metering purposes.

Considering now the circuit shown in Figs. 1 and 2, it will be understood that the signalling arrangements which need to be provided to indicate when the regenerator is full tocapacity, that is when forty impulses are stored therein, may comprise simply a modified off-normal spring operating cam on the regenerated mechanism.

This is arranged to open the off-normal contacts if the impulse receiving disc is rotated through forty steps away from the position of the sending disc. Since these contacts are also open in the normal position of the mechanism, a discriminating means is provided which comprises contacts on a relay held operated during and for a short interval after each train of received impulses. These arrangements will be better appreciated from the ensuing detailed description.

A description will first be given of the functioning of the circuit as shown, that is to say as an outgoing repeater with through switching on relay of the called party. In this case the incoming leads will extend from a battery feeding selectorwhile the outgoing negative and positive leads will connect with a junction.

When the repeater is taken into use, the loop extended across the incoming negative and positive conductors operates relay A which thereupon operates relay B. Relay B at armature b3 applies a guard earth to the P load and at armature b5 extends an earth over the negative outgoing junction line to operate the line relay in distant junction line circuit which starts up a finder switch in lmown manner, the usual cutoff relay contacts to earth on the positive line being omitted from the junction line circuit.

On reception of the first train of impulses, relay A responds and on each release relay B holds operated due to its slug while earth is extended over armatures al, bl, M3 and Th5 to energise the regenerator receiving magnet RM in order that the digits may be .stored. Relay C operates in parallel with the magnet and holds during the train due to its slug. At armature cl it brings up relay IP which has no function at this stage, and at armature 02 it energises the regenerator marking magnet Nil/L It should be mentioned that the regenerator comprises essentially a receiving ratchet wheel R which is rotated step by step under control of the magnet RM and which is arranged on one side of a fixed disc P carrying around its periphcry a row of forty pins. receiving disc R stores up energy in a clockspring to drive the sending disc S and thus actuate the impulse springs IMP and send out regenerated impulses of the correct character. Before the first digit is received the armature of the marking magnet MM is resting on a pin in the disc P which it has pushed forward to restrain the sending disc S. During the first train of pulses the energisation of the marking magnet due to operation of relay C tilts a lever carried by the receiving disc R out of engagement with the pins. At the end of the train the receiving disc will have been rotated a corresponding number of steps and on the release of relay C after a short interval due to its slug, the marking magnet MM is de-energised and thus allows the lever carried by the receiving disc R to tilt back towards the disc P thereby displacing into the path of the disc S a pin corresponding to the digit dialled. Hence if the successive digits dialled are 5, 4 and 1 pins numbers 5, 9 and 16 from the original resting position are displaced. It should be noted that the sending disc S is at present restrained by the pin which was displaced at the end of the previous call.

When the receiving disc R is first moved oifnormal, the off-normal springs NI close and thus when the marking magnet is restored at the end of the first digit the springs mm controlled by this magnet close and a circuit is completed over contacts NI to operate relay BY which thereupon locks by way of armature byl. These contacts also complete a circuit over armatures b2 and cl to holdrelay IP each time relay releases.

Further trains of incoming pulses are accepted and stored by the regenerator but no retransmission of the stored trains can commence until the distant line finder signals that it has found the calling junction.

When this occurs the cut-off relay operates in The rotation of the the usual manner and switches the junction line through to the distant incoming selector. Relay A in the incoming selector provides a battery connection to the negative line and an earth connection to the positive line as is the usual practice, and as a result relay I in the repeater circuit is now operated by way of resistance YB to the earthed positive line and at armature 1'! it completes an operating circuit for relay SW from the earthed P lead. Relay SW at armature swl locks independently of the armature il, at armatures sw2 and sw3 disconnects the battery and earth connections extending to the outgoing negative and positive conductors and substitutes in their place a bridge consisting of the regenerator impulse springs IMP and relays D and I which however are now short-circuited by armature byfi. Armature sw4 polarises relay D and armature sw5 completes a circuit from earth, off-normal contacts NI, fixed disc P which is in contact with the pin left projecting from the previous call, the reset pin. in the disc S which bears against the displaced pin, contacts sm, armatures D118 and $105 to short-circuit relay IP while at armature $206 an operating circuit is completed for relay IS in series with the regenerator sending magnet SM, the magnet being non-operative in this condition.

After a short interval relay IP releases and at armature ip2 disconnects relay IS which holds operated for a further short period due to its short-circuited upper winding. On the release of relay IS a circuit is completed from earth, armatures i102, by l and 2's3 to energise the sending magnet SM which now pushes the reset pin in the disc S to the right in order to restore the displaced pin in the disc P against which it is resting. On the operation of the magnet SM the contacts sm open and thus remove the shortcircuit from relay IP which immediately re-operates and at armature i122 re-operates relay IS and de-energi'zes the magnet SM.

As described in J. W. McClew and C. R. Woodlands application No. 79,830, filed May 15, 1936, the reset pin is now withdrawn thus releasing the stop pin displaced at the end of the first digit. During this rotation a fresh train of impulses corresponding in number to those received, but correct as regards ratio and speed, is generated at the springs IMP controlled from the regenerator and these impulses serve to set the switch at the distant exchange. When the reset pin in the disc S comes up against the displaced stop pin indicating the termination of the first series of impulses, relay IP is again short-circuited and in turn releases relay IS to produce another momentary operation of the sending magnet SM. Accordingly the disc S is released to generate a second series of impulses in the manner described. It will be appreciated that the reception and retransmission of impulses may go on simultaneously but that the two operations are independent of each other and that the sequential release of relays IP and IS in each case provides the necessary pause between successive series of impulses.

When ,all digits received have been retransmitted, the sending disc S will catch up with the receiving disc R, whereupon the off-normal contacts NI open and relays BY, IP and IS are released. Relay BY upon releasing re-inserts rclays D and I in the outgoing loop.

When the connection is completed and the called subscriber replies, battery is reversed over the called side of the circuit to operate the shunt field relay D which at armature dl operates relay RB from the earthed P lead. Relay RB at armature rbl locks independently of the armature dl, at armatures Th2 and Th3 disconnects the transmission bridge thereby releasing relays A and B and also extends the calling side of the circuit straight through to the succeeding switch, at armature rbd disconnects the impedance bridge relays D and I from the speaking circuit and at armatures Th5 and rbii disconnects the regenerator receiving magnet RM and marking magnet Ml/Irespectively. a

On the release of the connection at the end of the conversation, earth is removed from the P conductor by the controlling switch in the train whereupon relay RB'releases and the repeater is freed for further use.

Returning now to the point in the description where the distant line finder was set hunting for the calling junction, it will be appreciated that if there is a sufficient delay in finding, the number of impulses received on the regenerator may be in excess of its storage capacity. Assuming now i that a total of forty impulses is received and that relay SW still remains unoperated, at the end of the last train of impulses relay A remains operated and relay C commences to release. Since the device is now full to capacity the off-normal con tacts NI are opened in the manner described earlier and hence during the release time of relay C a circuit is completed at armature 03 to operate relay BR. over its lower winding in series with relay BY, the latter relay remaining operated in this condition, Relay BR. at armature brl locks over its upper winding, at armature br2 completes a holding circuit for relay BY which is independent of armature 03, at armature br3 disconnects the impulsing circuit to the regenerator receiving magnet RM and relay C and at armature br4 prepares a circuit for short-circuiting relay 1?. At armature br5 a busy tone transformer is connected up to the middle winding of relay A on to the incoming speaking conductors in a balanced circuit, while at armatures 2716 and M8 the battery and earth connections are removed from the outgoing leads thereby opening the start circuit to the finder at the distant exchange. On the release of relay C'a circuit is completed at armature cl to short-circuit relay IP whereupon the stored digits are retransmitted from the regenerator into an open circuit in readiness for the release of the connection by the calling party.

Should more than forty impulses be received in the above circumstances, the receiving disc R on being rotated forty steps away from the sending disc S is mechanically prevented from rotating further, while relay BR will be operated with the above-described functions.

Owing to the fact that the regenerator receiving magnet RM is operated on the reverse drive principle, there is a tendency for relay BR to operate in series with relay BY in the break period of the first impulse of the first trainreceived when relay C and the magnet RM areenergized but the NI contacts are not closed. Relay 0 however in addition [to completing an operating circuit for relay BR at armature c3,salso energizes the marking magnet at armature c2 and this magnet opens the operating circuit of relay BR at contacts mm. In order that there will be no possibility of relays BR operating during the operating to prevent relay BR from'operating in a normal manner during the release time of relay C- Considering now the functioning of the circuit as an outgoing repeater in which the transmission bridge is retained during conversation, the incoming leads will extend from a non-battery feeding selector. The dotted connections are omitted and in their place other connections are made between terminals 3 and 5, 4 and 6 and 8 and Ill. With those arrangements the reception and retransmission of the digits takes place in the manner described but when the calling party replies relay RB upon operating repeats the reverse battery conditions to the calling side of the circuit for metering or supervisory purposes.

On the release of the connection at the end of the conversation, relay A releases and is followed by relay B which opens the forward loop at armature b5 to release the switches in the distant exchange. It will be noticed that relay C is operated during the slow release period of relay B and in turn operates relay IP to maintain earth on the P conductor after the release of relay B. By this means a double guard is provided on the release trunk conductor P to ensure an adequate period for the release of the switches at the distant exchange before the repeater is again freed for further use. In the case where the repeater is adapted for through switching this double guard period would of course be provided from the preceding battery feeding switch.

In case the calling subscriber should release the connection prematurely, that is, by hanging up his receiver during dialling, relay A upon releasing disconnects relay B and operates relay C. Assuming that relay SW has not been operated to initiate retransmission of the stored digits, relay C at armature cl maintains relay IP, On the release of relays B, C and IP in turn, an earth is extended over armatures i102, M4 and is3 to energize the sending magnet SM whereupon the regenerator commences to retransmit its stored digits into an open circuit, a single pause comprising the release timeof relay IP being provided between each digit since the upper winding of relay IS is not now short-circuited at armature swt. When all the digits have been sent relay BY is released at the off-normal contacts NI, and at armature 22,112 earth is removed from the P conductor to free the repeater for further use.

In case the repeater is functioning in an incoming capacity, the circuit operation will be as previously described, but ona premature release of the connection it will be clearly desirable to guard the distant end of the junction against seizure until the regenerator is fully restored to normal. This is achieved by the extension of earth by way of armatures 173, by? and Th2 on to the incoming negative conductor during the period that relay BY remains operated and this serves to operate a relay at the distant outgoing end of the junction to' apply guarding conditions thereto.

In case the regenerator fails to retransmit all its stored impulses, relay BY holds operated to the oiT-normal contacts NI and as a result earth is maintained on common conductor H extending to delayed alarm equipment.

Referring now to the circuits of Figs. 3 and 4 which employs two'regenerators"connected in series, arrangements are made whereby the first mechanism on storing its full complement of digits transmits a signal to initiate a switching operation which transfers the succeeding incoming digits to the second mechanism. The stored cal digits are subsequently retransmitted in corrected form from each mechanism in proper sequence. In this case a slight modification is required on the first mechanism in that the special cam is arranged to re-open the off-normal contacts when the receiving disc has been rotated from thirty-one to forty steps ahead of the position of the sending disc; This is done since it will be appreciated that when the disc is in any position up to 30 the regenerator can still accept another digit of any value but in position 3! it could not accept a digit comprising ten impulses. A discriminating means is again provided in the form of contact of the C relay so that switching over from the first to the second mechanism occurs only at the termination of the digit which carries the receiving disc into positions 3| to 40.

Since the circuit follows along the same lines as that previously described only the difierences in the operation will be referred to in detail.

On the reception of the incoming pulses, relay A responds and. steps the receiving magnet RM to store them on the first regenerator. If there is a suflicient delay in finding, the calling junction line at the distant exchange, the receiving disc will be carried in response to one of the trains of impulses past position 30. At the end of this train, relays Aand B remain operated and relay C commences to release in the usual manner and during its release time earth is eX- tended over armatures c3 and 702 to operate relay BR. in series with relay BY which remains held. Relay BR upon operating locks up in series with relay BY at armature M2 and at armature brl operates relay K. Relay K thereupon at armature kl locks independently of armature brl, at armature k2 disconnects the original operating circuit for relay BR, at armatures R3 and k4 connects up circuits to the marking magnet 2M and the receiving magnet 2RM respectively of the second regenerator and at armature k5 prepares a circuit for relay 00.

Subsequent trains of incoming pulses are therefore received and stored by the second regenerator.

\Vhen the distant line finder finds the calling junction, relay SW operates and initiates the sending out of the stored pulses from the first regenerator in the normal manner by short circuiting relay IP.

When all digits stored therein have been retransmitted, the sending disc S catches up with the receiving disc R. whereupon the off-normal contacts NI open and restore relay BY, relay BR having been short-circuited and released by these contacts duringthe sending out. A circuit is now completed over armatures byZl and 105 to operate relay CO. Relay CO at armature 002 connects up the sending magnet ISM of the second regenerator, at armature 003 completes a reoperating circuit for relay BY from earth over the second regenerator off-normal contacts ZNI and at armature 004 completes a circuit to maintain relay IP which will be still holding operated due to its slug in spite of the opening of its original circuit at contacts Ni. On the re-operation of relay BY, earth is extended over contacts 2N], pin plate 2P, sending disc 2S and sending magnet interrupter contacts 2sm, armatures 005, by8 and sw5 to short-circuit relay IP. On the release of relay IF the sending out is initiated from the second rcgenerator which generates at its impulsing contacts 2IMP a fresh set of impulses corresponding to those stored.

If it should be so desired, the second mechanism might be, modified in the manner described in conjunction with Figs. 1 and 2 so that busy tone would be returned to the calling party if both mechanisms should become full to capacity.

A mechanical impulse repeater modified according: to the invention can be advantageously applied in a .discriminating selector repeater at a sub-satellite exchange especially where there is a shortage of junctions, when it is undesirable to take into use the junctions to the satellite and main ofiices until the dialling of a plurality of discriminating digits has indicated that it is necessary. Another application is in connection with impulse repeaters which are provided with multi-fee metering facilities in which case digit storage is also necessary until such time as access can be had to the common multi-fee metering equipment.

We claim: I 1. In an automatic circuit arrangement for an impulse regenerating device, means for transmitting trains of impulses to said device, marking means in said device stepped in accordance therewith, other stepping means in the device operated to transmit said trains of impulses in accordance with said markings, means for rendering said last means effective responsive to the initial step of said marking means, and means operated responsive to the marking means advancing a predetermined number of steps away from the transmitting means for rendering said first and said third means inefiective.

2. In an automatic circuit arrangement, an impulse regenerating device having two stepping members, means for transmitting impulses to the device for causing one of said members to step in accordance therewith, the other of said members operated subsequently to step in accordance with the movement of said one member for transmitting impulses, means for rendering said operation of said other member ineffective, and means for operating said last means responsive to said members becoming separated a predetermined amount.

3. In an automatic circuit arrangement, an impulse regenerating device having two stepping members, means for transmitting impulses to the device for causing one of said members to step in accordance therewith, the other of said members operated subsequently to step in accordance with the movement of said one member for transmitting impulses, means for preventing the operation of saidone member, and means for operating said last means responsive to said members becoming separated a predetermined amount.

4. In an automatic circuit arrangement, an impulse regenerating device having two stepping members, means for transmitting impulses to the device for causing one of said members to step in accordance therewith, the other of said members operated subsequently to step in accordance with the movement of said one member for transmitting impulses, and relay operated responsive to the members becoming separated a predetermined amount for controlling the further operations of the members in said device.

5. In an automatic circuit arrangement, an impulse regenerating device having two stepping members, said members having a normal position relative to one another, means for transmitting trains of impulses to the device for causing one of said members to step'awayfrom said position in accordance therewith, the other of said members operated in accordance with the stepping of said one member to transmit similar trains of impulses, and means operated when said one member has advanced a predetermined number of steps farther than said other member for disabling said first means.

6. In an automatic circuit arrangement, two stepping members, means for transmitting trains of impulses to operate one of said members, control means operated a first time by said one member to prepare the other of said members for operation and a second time by said one member to initiate said operation of said other member, means for at times initiating the operation of said other member before said second operation of the control means, and means for controlling the operation of said other member in accordance with said operation of said first member at said times to cause said other member to transmit trains of impulses similar to said first trains of impulses.

7. In an automatic circuit arrangement including an impulse generating device, an outgoing circuit, means for transmitting trains of impulses to said device, a marking member in said device operated responsive thereto, another member in the device subsequently operative to co-operate therewith and to retransmit said trains of impulses to said outgoing circuit, means operated at times over the outgoing circuit for initiating the operation of said other member, and means operated at other times by said marking member for initiating the operation of said other member.

8. In a circuit combination, an outgoing circuit, two impulse regenerating devices each having two mechanically co-operating members, means for transmitting impulse trains to the first of said devices, one member of said first device stepped responsive to certain of said trains, the other member of said first device operated subsequently to step in accordance with said movement of its cooperating member for transmitting impulses to said outgoing circuit, means operated when a certain relative position exists between the members of the first device for causing one member of the second of said devices to step responsive to subsequent trains of impulses transmitted by said first means, and means operated when normality is restored between the members of said first device for causing the operation of the other member of said second device to step in accordance with said movement of its co-operat ing member for transmitting impulses to said outgoing circuit.

9. In a storage arrangement, two storage devices, means for transmitting trains of impulses, means in the first of said devices for receiving and storing a plurality of said trains of impulses, means operated responsive to the storage of a predetermined total number of impulses in said first device to prepare the second of said devices for operation, and means operated responsive to the first termination of a train of impulses after said preparation of the second device to render said seconddevice effective to receive and store one or more successive trainsof said impulses.

WILLIE SAVILLE. AUSTIN HUGH WILLIAMS. 

